Tanks, reaction chambers, large pipes, and other vessels may have manways to enable service personnel to enter the vessel. Typically, a manway comprises a short stubpipe projecting perpendicularly from a wall of the vessel, having a radiating flange. The flange contains studs or bolt holes for accommodating fasteners enabling secure mounting of a closure over the manway. In ordinary operation, the closure is securely bolted to the flange to contain pressure and contents of the vessel.
From time to time, service personnel must enter the vessel when the latter is empty. This may be done for example, for inspections, repairs, cleaning, unclogging, installation of instrumentation, and for other purposes. It is often difficult for service personnel to enter a manway. For example, the nature of the chemicals used in the manway may make surfaces of the manway slippery, or otherwise hazardous to contact by hand, such as due to potential toxicity of residues of the substances contained in the vessel.
There exists a need to facilitate entry of service personnel into vessels through manways.